A wide variety of organopolysiloxanes are known in the art and have been used for a wide variety of purposes. This invention relates to those organopolysiloxanes having the above cone penetration and ultimate elongation properties which material also have a very high surface tackiness. These materials are useful as sealants and encapsulants to protect substrates from environmental exposure and are particularly useful in thin sheets or tapes having a thickness of 5 mm or less. Due to the surface tackiness and other properties of these materials, they are difficult to handle. The handling qualities can be improved by crosslinking the organopolysiloxane in a flexible matrix as disclosed in copending application U.S. Ser. No. 507,435 filed June 23, 1981 now abandoned. When such materials are wrapped around a substrate or applied to a substrate the exposed surface of the material remains tacky. It is desirable to provide such a material which has a reduced or non-tacky surface when installed on a substrate.
U.S. Pat. No. 4,163,082 to Romenesko discloses reducing or eliminating surface tack on organopolysiloxane gels or greases by applying to the surface of the gel or grease an additional layer of a liquid organopolysiloxane composition which is UV curable then curing the coating by ultraviolet radiation. U.S. Pat. No. 4,364,809 to Sato et al. relates to organopolysiloxanes cured to rubbery elastomer thin sheets but does not particularly address the desirability of having a non-tacky surface thereon.
Other references which illustrate the general background of organopolysiloxane materials, their preparation, curing, and the like include U.S. Pat. Nos. 4,196,273 to Imai et al.; 3,624,022 to Ross; 4,064,027 to Gant and 4,163,081 to Schulz.
U.S. Pat. No. 2,762,609 to Lewis et al. relates to organopolysiloxanes which in one aspect are partially cured on one surface and left uncured on the other surface then installed on a substrate and then fully vulcanized in place.
The disclosures of the above patents are incorporated herein by reference with respect to the conventional and general background relative to the types of organopolysiloxane materials which may be crosslinked, the methods of crosslinking polysiloxanes, the initiators used to initiate the crosslinking and other conventional aspects of the organopolysiloxane art.